Something, or thousands of somethings, can be hiding in your facility this winter. They’re “overwintering” pests, and they can be quite a nuisance.
Overwintering – what does it actually mean? The dictionary definition is to last through the winter. Pests resort to a variety of self-preservation tactics pests use to survive the season and reemerge in the spring. Overwintering pests don’t reproduce, feed or develop indoors – they’re inactive, until they’re not.
Signs of Overwintering
As long as temperatures stay cold, overwintering pests will remain inactive and out of sight. You won’t know you have overwintering pests. But, when temperatures warm, even for a few mild days, the pests “wake up” and move toward the warmth. Many of these pests won’t make it outside, which means they show up in your facility.
Pests flock to the sunny side of buildings; and when we say “flock,” we mean hundreds and even thousands of tiny bugs clustered together in a very visible way.
You may find these pest groupings near windows, doors or even artificial light. If your building is warmed by the sun, the artificial light may be enough to trick these pests into emerging from their hiding spots.
Pests that Overwinter
Boxelder Bugs: About a half-inch long, boxelder bugs are black with orange or red markings including three stripes behind their head. Young or nymph boxelder bugs are bright-red when they first hatch and slowly change to the orange/black combination.
Cluster Flies: Cluster flies are just under a half-inch long, slightly larger than the common housefly. They have two large eyes with overlapping, transparent wings. They’re often grey on the underbelly and golden on top, giving off a golden sheen.
Lady beetles: Lady beetles, unlike ladybugs, are shiny, dome-shaped insects. Most are red or orange with black spots.
Brown Marmorated Stink Bugs: These bugs are most common on the East Coast. Stink bugs can range from one half to three quarters of an inch long. They have a very distinct shield shape with a marbled body. Stink bugs have two long antenna and six legs. When bothered, they release their infamous foul odor.
How to Rid Yourself of Overwintering Pests
Insecticides will not prevent the insects from emerging. They must be physically removed. We suggest a vacuum to suck up pests both dead and alive.
To kill these pests as they emerge in the spring, install a fly light, which will attract the pests looking for light and warmth.
To keep pests out, install door sweeps, seal cracks with high quality silicone caulk, and fill holes around drains and utilities with steel wool. Once these overwintering pests have made your warehouse their winter home, the only solution is physical removal and planning ahead for next winter.
If you notice a moderate to severe amount of overwintering pests, we suggest calling a pest management professional. They can help set a plan in motion to remove overwintering pests as they emerge and prevent them next season.
By Nic Ellis, board-certified entomologist, Western Pest Services